Subarachnoid cisterns


The subarachnoid cisterns are spaces formed by openings in the subarachnoid space, an anatomic space in the meninges of the brain. The space separates two of the meninges, the arachnoid mater and the pia mater. These cisterns are filled with cerebrospinal fluid.

Structure

Although the pia mater adheres to the surface of the brain, closely following the contours of its gyri and sulci, the arachnoid mater only covers its superficial surface, bridging across the gyri. This leaves wider spaces between the pia and arachnoid and the cavities are known as the subarachnoid cisterns.
Although they are often described as distinct compartments, the subarachnoid cisterns are not truly anatomically distinct. Rather, these subarachnoid cisterns are separated from each other by a trabeculated porous wall with various-sized openings.

Cisterns

There are many cisterns in the brain with several large ones noted with their own name. At the base of the spinal cord is another subarachnoid cistern: the lumbar cistern.
Some major subarachnoid cisterns:
  1. The vertebral artery and the origin of the posterior inferior cerebellar artery
  2. The ninth, tenth, eleventh and twelfth cranial nerves
  1. The basilar artery and the origin of the anteroinferior cerebellar artery
  2. The origin of the superior cerebellar arteries
  3. The sixth cranial nerve
  1. The optic chiasm
  2. The bifurcation of the basilar artery
  3. Peduncular segments of the posterior cerebral arteries
  4. Peduncular segments of the superior cerebellar arteries
  5. Perforating branches of the PCA
  6. The posterior communicating arteries
  7. The basal vein
  8. The third cranial nerve, which passes between the posterior cerebral and superior cerebellar arteries
  1. The seventh and eighth cranial nerves
  2. The anteroinferior cerebellar artery
  3. The fifth cranial nerve and the petrosal vein
  1. The great cerebral vein
  2. The posterior pericallosal arteries
  3. The third portion of the superior cerebellar arteries
  4. Perforating branches of the posterior cerebral and superior cerebellar arteries
  5. The third portion of the posterior cerebral arteries
  6. The basal vein
  7. The posterior cerebral artery
  8. The superior cerebellar artery
  9. The fourth nerve
  1. The anterior choroidal artery
  2. The medial posterior choroidal artery
  3. The basal vein
  1. The internal carotid artery
  2. The origin of the anterior choroidal artery
  3. The origin of the posterior communicating artery
  1. The middle cerebral artery
  2. The middle cerebral veins
  3. The fronto-orbital veins
  4. Collaterals to the basal vein
  1. The anterior cerebral arteries
  2. The anterior communicating artery
  3. Heubner's artery
  4. The hypothalamic arteries
  5. The origin of the fronto-orbital arteries
It is of clinical significance that cerebral arteries, veins and cranial nerves must pass through the subarachnoid space, and these structures maintain their meningeal investment until around their point of exit from the skull.